This invention relates to a structure enabling the adjoining expansion of devices (herein this is called an “adjoining expansion structure”).
For example, when stacking a plurality of synthetic resin mold products, the adjoining expansion structure is often required for aligning the respective products and coupling them together.
A first related art will be described with reference to FIGS. 1A to 1C.
As shown in FIG. 1A, a parent device 31 is configured as a rectangular parallelepiped box and an expansion metal fitting 32 is configured as a rectangular plate. The expansion metal fitting 32 is provided with a total of four hooks 32a at two portions near the middle of its rear side and at two portions near rear corners of its left and right sides. The expansion metal fitting 32 is further provided with screw-fixing plate-like portions 32b at two portions near the middle of its front side. Further, holes 32c for insertion of screws are provided near four corners of the expansion metal fitting 32.
As indicated by downward arrows in FIG. 1A, the expansion metal fitting 32 is placed on an upper surface of the parent device 31 and fixed to the parent device 31 by four screws (not shown).
As shown in FIG. 1B, a child device 33 is configured as a rectangular parallelepiped box having the same size as the parent device 31. The child device 33 is provided with hook engaging portions (not shown) at portions corresponding to the four hooks 32a of the expansion metal fitting 32. The child device 33 is further provided with screw holes 33a at two portions near the middle of its front lower portion.
As shown in FIG. 1C, the child device 33 is placed on the expansion metal fitting 32 so that the hook engaging portions of the child device 33 engage the hooks 32a of the expansion metal fitting 32, respectively. Then, two screws 34 are inserted into the two screw-fixing plate-like portions 32b of the expansion metal fitting 32 and threaded into the two screw holes 33a of the child device 33. As a result, the child device 33 is coupled to the parent device 31. The expansion metal fitting 32 is seen between the devices 31 and 33.
A second related art will be described with reference to FIGS. 2A and 2B.
As shown in FIG. 2A, a parent device 41 is made of a synthetic resin and configured as a rectangular parallelepiped box. Hook engaging holes 41a are formed at three portions on one side of the parent device 41. A child device 42 is made of a synthetic resin and configured as a rectangular parallelepiped box. Hooks 42a are formed to project at three portions on one side of the child device 42.
The child device 42 is coupled to the parent device 41 as shown in FIG. 2B. Since an expansion metal fitting is not used between the devices 41 and 42, the design is not marred. However, since the hooks 42a and the hook engaging holes 41a are each part of the mold product, the structural strength is insufficient.
A third related art will be described (see, e.g. Japanese Unexamined Utility Model Application Publication (JP-U) No. Sho 62-70480). A plate member of a coupler has four pairs of L-shaped pawls and a pair of fixing pieces. After fitting the L-shaped pawls into coupling surfaces of two devices to be coupled together, the fixing pieces are screwed to the devices, respectively.
A fourth related art will be described (see, e.g. Japanese Unexamined Utility Model Application Publication (JP-U) No. Hei 04-10376). Using feet of an upper device housing and foot receivers of a lower device housing as positioning guide means, the housings are stacked together. In this event, L-shaped metal fittings of the upper device housing are brought into engagement with U-shaped metal fittings of the lower device housing, respectively. Then, fixing screws are respectively inserted into holes of the U-shaped metal fittings and holes of the L-shaped metal fittings and then tightened, so that the housings are fixedly coupled together.
A fifth related art will be described (see, e.g. Japanese Unexamined Patent Application Publication (JP-A) No. 2002-284168). When grips of a container box are respectively placed in grip cutout portions, engaging pawls are respectively brought into engagement with engaging rods of another container box located below. Accordingly, the two container boxes are coupled together. When the grips are raised from the grip cutout portions, the engaging pawls release the engagement with the engaging rods. Accordingly, the two container boxes are released from the coupling.
The first to fifth related arts each have at least one of the following drawbacks.
1. Since an expansion metal fitting coupling together a parent device and a child device is seen from the outside, the design properties of the devices are reduced.
2. The strength of a structure coupling together a parent device and a child device is weak.
3. The structure coupling together a parent device and a child device is complicated.